powerpc/eeh: Fix recursive fenced PHB on Broadcom shiner adapter

powerpc/eeh: Fix recursive fenced PHB on Broadcom shiner adapter

Similar to commit b6541db ("powerpc/eeh: Block PCI config access
upon frozen PE"), this blocks the PCI config space of Broadcom
Shiner adapter until PE reset is completed, to avoid recursive
fenced PHB when dumping PCI config registers during the period
of error recovery.

   ~# lspci -ns 0003:03:00.0
   0003:03:00.0 0200: 14e4:168a (rev 10)
   ~# lspci -s 0003:03:00.0
   0003:03:00.0 Ethernet controller: Broadcom Corporation \
                NetXtreme II BCM57800 1/10 Gigabit Ethernet (rev 10)

Signed-off-by: Gavin Shan <gwshan@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>